The gene regulatory network for root epidermal cell-type pattern formation in Arabidopsis

Abstract

A fundamental aspect of multicellular development is the patterning of distinct cell types in appropriate locations. In this review, the molecular genetic control of cell-type pattern formation in the root epidermis of Arabidopsis thaliana is summarized. This developmental system represents a simple and genetically tractable example of plant cell patterning. The distribution of the two epidermal cell types, root-hair cells and non-hair cells, are generated by a combination of positional signalling and lateral inhibition mechanisms. In addition, recent evidence suggests that reinforcing mechanisms are used to ensure that the initial cell fate choice is adopted in a robust manner.

Fig. 1.

Photographs of roots from wild-type, wer mutant, and cpc mutant Arabidopsis plants. The wer mutant produces excessive root hair cells; whereas the cpc mutant has a reduced number of root hair cells. The bar length is 200 μm.

Fig. 2.

A model to explain cell-type patterning in the Arabidopsis root epidermis. The SCM receptor preferentially represses WER transcription in the H cell position to instigate the pattern formation. The two distinct cell types arise by the differential accumulation of the WER-GL3/EGL3-TTG transcriptional complex, which directs non-hair cell differentiation. (This figure is available in colour at JXB online.)